[HN Gopher] Printegrated Circuits: Merging 3D Printing and Elect...
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       Printegrated Circuits: Merging 3D Printing and Electronics
        
       Author : rbanffy
       Score  : 61 points
       Date   : 2025-06-30 11:30 UTC (11 hours ago)
        
 (HTM) web link (spectrum.ieee.org)
 (TXT) w3m dump (spectrum.ieee.org)
        
       | p0px wrote:
       | Wanted to show off a similar project I did. I used tracks for
       | dupoint wires in my model and used the GPIO pins to push through
       | the wires to create connections.
       | 
       | For the LED eyes, I created THT connectors using the ends of the
       | dupoint wire ends.
       | 
       | https://makerworld.com/en/models/672277-wabbt-wifi-bluetooth...
        
       | nickpinkston wrote:
       | People have been doing this for a long time, but it feels a
       | little too purist to me.
       | 
       | The components will still be the same, so you'll still need some
       | kind of pick-n-place functionality to make anything, so why not
       | just have another print head for making the traces / doing the
       | PnP?
       | 
       | The head could lay copper wire/foil tape for conductors and do
       | standard PnP from trays / reels of components, which you'll need
       | either way.
       | 
       | It would be a little more geometrically limited than what this
       | post imagines, but it would have the upside that it would
       | actually work today and with most real electronics applications,
       | unlike the low performance conductors made via conductive
       | polymers as the OP's process imagines.
        
         | Aurornis wrote:
         | > The head could lay copper wire/foil tape for conductors
         | 
         | Sounds awesome, but this is an extremely hard problem to solve.
         | You can't simply lay down wire or foil into arbitrary shapes on
         | 3D surfaces.
        
           | Lerc wrote:
           | If you had a wire feeder with a actuated barrier just past
           | the tip you can fairly easily bend wire into controlled
           | shapes pretty well. If you printed channels for them to sit
           | in, I think they could be placed.
        
             | joshmarinacci wrote:
             | When I worked at Markforged we had a printer that could put
             | solid carbon fiber threads into the print using a second
             | extruder (on the same print head), so it's certainly
             | possible. It was $20k, though. Getting this down to
             | something accessible to hobbyists is the challenge. I think
             | it will happen one day, though.
        
             | Aurornis wrote:
             | CNC wire benders exist, but they're solving a different
             | problem: They bend the wire in free space, not on to a
             | surface. You would have to design the part and the wire
             | such that the part never comes around into the space
             | occupied by the head, which would limit it to only very
             | basic and small shapes.
        
               | Xmd5a wrote:
               | Maybe lay chains instead of wires. Apply tension to the
               | chain, ensuring that it conducts current and use fast
               | solidifying glue to fix it in place/make it adhere to the
               | surface/insulate it.
        
               | Lerc wrote:
               | I was thinking you'd print a channel where the wire would
               | be placed, bend the wire to the shape of the channel,
               | place it, and print over the top.
               | 
               | Some geometries wouldn't work, but it would be sufficient
               | to make shapes like you see in breadboard connections
               | (up, zigzag around, down)
        
           | nickpinkston wrote:
           | Yea, agreed it's pretty hard, though with some tradeoffs it
           | could be done pragmatically.
           | 
           | I would probably slightly overbuild the plastic and then use
           | a heated tool to form the smoother surfaces the wire/foil
           | would go in/on.
           | 
           | I've also seen laser sputtering of copper, etc. which could
           | be the another approach, something similar is used for
           | metalizing plastic already, though contamination would need
           | to be controlled to maintain low resistivity.
        
         | Lerc wrote:
         | A PnP placing the components upside down onto a surface printed
         | by another head would be interesting. You could align the
         | heights of the resting surfaces to optimise pads needing to be
         | connected being on the same plane. I'd still want to lay copper
         | but if you had the ability to squirt a little solder paste from
         | (yet another) head, you could stack everything with wire
         | connections into a very 3d circuit.
         | 
         | If the base material was thermally conductive you could have a
         | heatsink block with the circuit embedded in it.
        
         | crote wrote:
         | I think the "printegrated circuits" approach is roughly the
         | right level of abstraction.
         | 
         | 3D Printing the PCB itself is pretty much impossible for any
         | non-trivial application. Doing multi-layer PCBs with 0.20mm
         | wide traces, spaced 0.20mm apart? Forget it, not happening -
         | and requirements like those are _standard_ for hobbyist-level
         | chips like the RP2040 these days.
         | 
         | And if you're not printing your own PCB, what's left is module-
         | level assembly and connectivity. In other words, just printing
         | a bunch of wires.
        
         | zakqwy wrote:
         | For this in 2D, see Sam's thesis, 6.3.3 (p. 86, CNC wire
         | plotting). 3D would add a lot of challenges.
         | 
         | https://cba.mit.edu/docs/theses/19.09.calisch.pdf
        
         | tdeck wrote:
         | This reminds me a bit of Multiwire, a somewhat unusual circuit
         | manufacturing technique from the 1980s. A machine laid down
         | wires and then encased them in resin. The best info I can find
         | is this slide deck:
         | 
         | https://www.swtest.org/swtw_library/2013proc/PDF/SWTW13-22.p...
         | 
         | I believe this technique was used in the Three Rivers PERQ
         | computers. Here is an image of one of their PCBs
         | https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg...
        
       | seveibar wrote:
       | There's a lot of potential for desktop rapid-prototyping with
       | electronics. I think one of the things that is killing us is the
       | tooling. One of the reasons I started building an autorouter was
       | because I wanted to be able to have different "build targets"-
       | e.g. a build target that is a PCB with no vias and only 0 ohm
       | resistors (jumpers). If our EDA tooling supported different build
       | outputs, then we could have earlier prototypes built with less-
       | than-ideal equipment (e.g. conductive 3D printed filament, as the
       | article suggests)
        
       | xg15 wrote:
       | On the one hand, I like the idea. On the other hand, I dread a
       | future where you need an X-Ray and/or MRT machine to be able to
       | inspect any kind of electronic device. And don't even think of
       | disassembling or repairing...
        
       | bitwrangler wrote:
       | Has anyone used dark color 3D filament printed onto copper clad
       | PCB as photo resist or etch resist?
       | 
       | It might be tricky printing PLA directly to copper clad PCB, but
       | then you could expose the board to UV or etchant to make the PCB
       | traces. Then remove the PLA plastic to expose the copper traces.
        
         | longtimelistnr wrote:
         | assumedly much much easier to buy a cheap vinyl cutter, but
         | interesting idea
        
         | fainpul wrote:
         | The toner transfer method uses a similar process and is
         | probably easier. You don't need a 3D printer, but one of those
         | laminating machines instead.
        
       | rkagerer wrote:
       | Anyone remember the Next Dynamics NexD1 Kickstarter?
       | 
       | It was pitched back in 2017 as a "Multimaterial & Electronics"
       | printer. Got to half a million or so in pledges before some of
       | the backers uncovered serious red flags and Kickstarter suspended
       | the campaign.
       | 
       | Hope this effort fares better.
        
       | monday_ wrote:
       | I have been thinking about adding conductive traces a-la PCB to
       | 3D prints in a DIY setting for a while. Obviously, conductive
       | filaments exist - but they are not remotely in the same category
       | as copper.
       | 
       | My initial hope was that doping PLA, PETG or some other material
       | with a conductor and then applying strong variable magnetic field
       | near the print head to force creation of conductive domains while
       | the filament is amorphous and hot. This turned out to be not
       | feasible, as O3 explained to me repeatedly, over hours of chats.
       | 
       | A simpler and surprisingly workable solution appears to be adding
       | a second printing head loaded with tin. Tin is not as good as
       | copper - but it's still leagues ahead of conductive filaments. To
       | offset the poor conductivity you can use thin, but very broad
       | traces.
       | 
       | A speculative approach would work like this:
       | 
       | 1. Print PETG layers using a regular filament, but leave "baths"
       | for tin traces. A bath should be an opening at least 2-3
       | millimeters tall, to account for the surface tension.
       | 
       | 2. After N layers, fill the baths from the tin head. Tin melting
       | point is near PETG, but it would cool rapidly and, hopefully,
       | weld to the plastic.
       | 
       | This way you could probably integrate a pcb into a print. I
       | haven't tried that, but i recall people actually trying to print
       | with tin - so that part is at least not a complete fantasy.
        
       | pedalpete wrote:
       | We are starting to see metal filaments and even this copper
       | one[1]. Multi-filament fdm printers just might be able to make
       | some rather large circuits. I doubt we'll get down to 0.2mm
       | tracers, but if size isn't an issue, we can do better than the
       | conductive carbon tpu(?) filaments which are common today.
       | 
       | [1] https://www.gsc-3d.com/3d_materials/copper-filament/
        
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